Fig. 1: Bone marrow stroma-derived soluble factors promote ALCAM-knockdown myeloma cell side population.

A Hoechst staining of CTR-KD or AL-KD MM cells (RPMI8226 or MM.1S) cultured in regular medium (CTR-M) or BMSC-conditioned medium (BMSC-M) for 48 h. The numbers indicate the percentage of SP cells. B Hoechst staining of AL-KD1 and AL-KD2 RPMI8226 cells cultured in regular medium (CTR-M) or BMSC-conditioned medium (BMSC-M) for 48 h. C Schematic graph: After cell sorting, SP cells were labeled with red fluorescent dye, and MP cells were labeled with CFSE. The labeled SP and MP cells were re-mixed with the ratio (SP:MP = 2:98). D SP cell proliferation was examined by flow cytometry for red fluorescent intensity dilution. E Fluorescence confocal microscopy of MM cells (green) and BMSCs (red) under 3D printing. F Hoechst staining of RPMI8226 cells, followed by cell sorting to isolate SP- and MP-only MM cells. The cells were used for the set of colony formation assay (left panel). Statistical results from the colony formation assays (right panel). Data are the mean of three independent experiments in three replicates. *p < 0.05.